(內(nèi)蒙古工業(yè)大學(xué) 材料科學(xué)與工程學(xué)院，呼和浩特 010051)
摘 要: 采用基于密度泛函理論的第一性原理方法，計算了含Ca鎂合金主要第二相(Al2Ca、Mg2Ca、Mg17Al12)不同晶面的費米能級、真空能級和電子功函數(shù)和本征電勢差，分析添加Ca鎂合金耐腐蝕性質(zhì)的電子機制。電子功函數(shù)結(jié)果表明：Mg17Al12電子功函數(shù)的平均值大于Mg基體的電子功函數(shù)，在腐蝕中Mg17Al12充當(dāng)陰極相；Al2Ca電子功函數(shù)的平均值與Mg基體的電子功函數(shù)相同，在腐蝕中與基體的電子功函數(shù)相仿；Mg2Ca電子功函數(shù)的平均值小于Mg基體的電子功函數(shù)，在腐蝕中Mg2Ca充當(dāng)陽極相。本征電勢差結(jié)果表明：Al2Ca和Mg2Ca與Mg基體的電勢差低于Mg17Al12與基體的電勢差，含Ca鎂合金的耐腐蝕性得到加強。
關(guān)鍵字: 鎂合金；本征電勢差；第二相；電子功函數(shù)；電偶腐蝕；第一性原理
（School of Material Science and Engineering, Inner Mongolia University of Technology, Hohhot 010051, China）
Abstract:The Fermi level, vacuum level, electronic work function and the intrinsic potential difference of the main second phases (Al2Ca, Mg2Ca, Mg17Al12) of magnesium alloy with Ca contents were calculated by using the first-principles method based on density functional theory. The electronic mechanism of the corrosion resistance of Mg alloy with calcium contents was analyzed. The results of electron work function show that the mean electron work function of Mg17Al12 is larger than that of Mg matrix, and Mg17Al12 acts as cathode phase in corrosion. The mean electron work function of the Al2Ca is the same as that of the Mg matrix, which is similar to the matrix in corrosion. The average value of Mg2Ca electron work function is smaller than that of Mg matrix and acts as anode phase in corrosion. The results of intrinsic potential difference show that the potential difference between Al2Ca, Mg2Ca and Mg matrix is lower than that between Mg17Al12 and the matrix, the corrosion resistance of Mg alloy with calcium contents is strengthened.
Key words: magnesium alloy; intrinsic potential difference; second phase; electronic work function; galvanic corrosion; first-principles
